The skin is the largest organ of human body, and a dermatoscope is usually utilized to conduct external optical imaging of this organ, check the health condition of skin tissue, and diagnose neoplastic lesions. The dermatoscope is expensive, and usually requires to be used repeatedly, and each time when used, the front-end detection working surface thereof fits human skin adhered with dusts and bacteria, and it is easy to cause cross-infection after repeated use. Therefore, the detection working surface of the dermatoscope must be disinfected after each use, which is fussy to operate, and is a waste of time; it is likely to wear the lens surface after many times.